Analytical energy gradient in variational calculations of the two lowest P3 states of the carbon atom with explicitly correlated Gaussian basis functions

Keeper L. Sharkey, Sergiy Bubin, Ludwik Adamowicz

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Variational calculations of ground and excited bound states on atomic and molecular systems performed with basis functions that explicitly depend on the interparticle distances can generate very accurate results provided that the basis function parameters are thoroughly optimized by the minimization of the energy. In this work we have derived the algorithm for the gradient of the energy determined with respect to the nonlinear exponential parameters of explicitly correlated Gaussian functions used in calculating n -electron atomic systems with two p -electrons and (n-2) s -electrons. The atomic Hamiltonian we used was obtained by rigorously separating out the kinetic energy of the center of mass motion from the laboratory-frame Hamiltonian and explicitly depends on the finite mass of the nucleus. The advantage of having the gradient available in the variational minimization of the energy is demonstrated in the calculations of the ground and the first excited P3 state of the carbon atom. For the former the lowest energy upper bound ever obtained is reported.

Original languageEnglish
Article number184106
JournalJournal of Chemical Physics
Volume132
Issue number18
DOIs
Publication statusPublished - 2010
Externally publishedYes

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Hamiltonians
Carbon
Atoms
gradients
Electrons
carbon
atoms
Excited states
Kinetic energy
optimization
electrons
energy
center of mass
kinetic energy
nuclei
excitation

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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Analytical energy gradient in variational calculations of the two lowest P3 states of the carbon atom with explicitly correlated Gaussian basis functions. / Sharkey, Keeper L.; Bubin, Sergiy; Adamowicz, Ludwik.

In: Journal of Chemical Physics, Vol. 132, No. 18, 184106, 2010.

Research output: Contribution to journalArticle

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